ESC capacitors

Joined
Oct 10, 2015
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Is this something I have to worry about? Never seen diy eboard instructions talking about this, and I'm an electronics noob. I just don't want to waste a $120 hobbywing ezrun

It's the number 4 of the instructions. Sorry if it's too small to read.

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Adding low-ESR capacitors to the red/black power inputs will suppress voltage ripple, which will help the ESC survive. The capacitors are usually $2 each.
 
Nordle said:
On 10S and VESC, can i use 50V capacitors instead of the 63V ones?
These for example? http://de.aliexpress.com/item/50V10...itor-50V-1000UF-Volume-13X20/32573701624.html I would like the form factor with 4 of those along the side of the vesc and already ordered them:D


You can use 50V capacitors since 10S is 42.0V. There's nothing wrong with using capacitors with a voltage higher than the system's voltage you will be running at. The important thing is the capacitance and equivalent series resistance (ESR) property for choosing a capacitor for your use.
 
I wouldnt risk anything and go for 63V - the price difference is just irrelevant really and the inductance of the wires may induce higher voltages than the applied battery voltage. thats why you should probably use capacitors with a healthy safety margin ontop of the battery voltage. :)
 
A few years ago there were several ebike builders experimenting with RC drives. A lot of experimentation went into finding the best possible capacitors. The lower the voltage of the capacitor, the lower the resistance, which is better for absorbing voltage ripple. Of course too low a max voltage and the $2 capacitor will pop. 50V caps are good for up to 11S (4.2V X 11 = 46.2V), 63V caps are good up to 14S (4.2V X 14 = 58.8V).

Having a long red/black power cable from the battery to the ESC will make ripple worse, so it should be short and fat. But the three phase wires from the ESC to the motor can be as long as you want. There are two bare wires coming out of the capacitor, one will be positive, and the other negative. Attach all of the negative leads onto the black battery wire, and all the positive leads onto the red battery wire.

I'm told the uF number (physical size) of the cap doesn't help us at all (bigger is not better), its only the other numbers that are of concern.

resistance, max voltage
16 mOhm, 50V, 1000uF, http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P12393-ND
17 mOhm, 63V, 1800uF, http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=565-1731-ND
 
I'm so sorry guys. I really suck at this. If it's good for 10s, and I'm only running it on 6s, am I good or what?

Alright so I'm using "Hobbywing EZRUN max8 v3 150A" ESC. It has 3 capacitors built in, but right now I don't know the specs for them. The box came with 4 more capacitors heat shrink wrapped as shown in the third picture.

My setup is:
-150A hw ezrun esc
-6s1p 5Ah 20c Zippy parallel with two 3s1p 5Ah 20c Zippy in series which makes it 6s
-NTM prop drive 50-60 270 kv which max rated watt I believe is 2400W.
 
The instructions say something like I need to wire in the extra capacitors if I'm using 6s (which I am) AND if the weight exceeds 7kg. Wth does the weight have to do with electronics? That throws me off. Most famous tutorial never talk about this. Idk if my version is different or something.
 
Another noob/stupid question(s): Is it ok to wire 6s1p 5Ah 20c zippy and 6s1p 5Ah 20c zippy (made from two 3s1p in series) in parallel? They are same brand and capacity.

Also for charging. I bought this $11 "charging board" I thought it had fancy circuit in it which alternately charges multiple batteries with same cell count and capacity, but it's basically just putting the balance connector and power jacks in parallel. Can I just skip this, and make my own from $3 parts, and wire them in parallel? Is the board just for neatness or what?

Sorry for noob questions.
 
4 comments in a row, but the reason why I'm going to use one 6s and two 3s in series to make 6s setup is mostly because of aesthetics. The 6s 5Ah packs are like 2"x2"x6" big while the 3s 5Ah packs are like 1"x2"x6". I have to make 2.5 inch thick box, and it wont look as low profile.
What I'm gonna do is set the 6s on the middle and 3s on the sides. Similar design concept of a penny board. This way the sides shows as 1.5 inch thick instead of 2.5
 
Wth does the weight have to do with electronics?

These ESCs are made for RC planes, and they normally accelerate to top speed in just a second. When you have it trying to accelerate a heavy load, you will experience heavy voltage ripple and voltage spikes (they are not designed for that). You can add hall sensors and run a 6-FET ebike controller to completely avoid that issue, and it will be cheaper, but...it will also be larger and heavier. Much larger.

I'm so sorry guys. I really suck at this. If it's good for 10s, and I'm only running it on 6s, am I good or what?

You're good.

Is it ok to wire 6s1p 5Ah 20c zippy and 6s1p 5Ah 20c zippy (made from two 3s1p in series) in parallel?

If there is any voltage difference, there will be a rapid "equalization" when you connect them. Charge them both to the exact same voltage, then make the final connection through a large resistor, like a 100W lightbulb. Once they are equalized, they will stay at the same voltage as long as they remain connected. They will charge and discharge together.

Is the board just for neatness or what?

Yeah, its just for someone who doesn't want to mess around with a soldering iron. Easy to make your own balance harness.
 
spinningmagnets said:
Wth does the weight have to do with electronics?

These ESCs are made for RC planes, and they normally accelerate to top speed in just a second. When you have it trying to accelerate a heavy load, you will experience heavy voltage ripple and voltage spikes (they are not designed for that). You can add hall sensors and run a 6-FET ebike controller to completely avoid that issue, and it will be cheaper, but...it will also be larger and heavier. Much larger.

I'm so sorry guys. I really suck at this. If it's good for 10s, and I'm only running it on 6s, am I good or what?

You're good.

Is it ok to wire 6s1p 5Ah 20c zippy and 6s1p 5Ah 20c zippy (made from two 3s1p in series) in parallel?

If there is any voltage difference, there will be a rapid "equalization" when you connect them. Charge them both to the exact same voltage, then make the final connection through a large resistor, like a 100W lightbulb. Once they are equalized, they will stay at the same voltage as long as they remain connected. They will charge and discharge together.

Is the board just for neatness or what?

Yeah, its just for someone who doesn't want to mess around with a soldering iron. Easy to make your own balance harness.
Thank you so much for the answers. Finally got off so much weight off my shoulders.
 
spinningmagnets said:
I'm told the uF number (physical size) of the cap doesn't help us at all (bigger is not better), its only the other numbers that are of concern.

hm, I recently had a VESC running that kept crashing under load, I really didnt know what to do, but I finally tried increasing cap size by replacing the 3x 580uF caps with 2x 2200uF which I had around the house somewhere, i.e. higher esr (which surely isnt better) and higher capacity. bottom line: the vesc was stable with the new caps. shouldnt a larger capacity be better for smoothing out the input voltage?
 
I dont tested your Hobbywing Controller so far.
But i used the Quicrun150A, the Xerun150A, the EzrunPro150A in many builds on 6S.
I never used any external Capacitors, got never a Problem with these ESC´s as long i kept the motorwires short!
 
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